Benchmark Testing of Generic Prismatic Planing Hull (GPPH) for Validation of CFD Tools

2017 ◽  
Author(s):  
Evan J. Lee ◽  
Christine C. Schleicher ◽  
Craig F. Merrill ◽  
Anne M. Fullerton ◽  
Jayson S. Geiser ◽  
...  
Keyword(s):  
Uncertainty Analysis ◽  
High Speed ◽  
Model Performance ◽  
Verification And Validation ◽  
Experimental Results ◽  
Naval Research ◽  
Naval Academy ◽  
University Of Iowa ◽  
United States Naval Academy ◽  
Calm Water

Model tank testing with the intent for verification and validation of numerical simulations carries its own unique set of challenges. As a part of an Office of Naval Research (ONR) project to obtain better physical understanding of the dynamic response of high speed craft, Naval Surface Warfare Center, Carderock Division, (NSWCCD), United States Naval Academy (USNA) and University of Iowa have been comparing experimental results and CFD predictions of planing hulls. To obtain a comprehensive set of model scale experimental data for assessing of CFD tools, a representative planing hull with a realistic bow shape, the Generic Prismatic Planing Hull (GPPH), was designed by NSWCCD. The GPPH is based on a notional full–scale hull about 12.8 m (42.8 ft) long with a 15.9 metric ton (35,000 lb) displacement. A detailed study of the model performance in calm water was conducted at NSWCCD. These calm water tests were used for the verification and validation of the CFD tools. Uncertainty analysis was conducted to provide confidence intervals on the experimental results. Uncertainty analysis was also performed on the mass property measurements, demonstrating the level of bias uncertainty associated with establishing the model baseline. The experimental uncertainty was combined with the numerical uncertainty to determine the validation uncertainty, which provides a benchmark for validating CFD tools. The calm water CFD predictions show agreement with the experimental results.

Numerical Simulation of Short Duration Hydrodynamic Impact

2014 ◽  
Author(s):  
Thomas C. Fu ◽  
Thomas T. O’Shea ◽  
Kyle A. Brucker ◽  
Carolyn Q. Judge ◽  
Christine M. Ikeda ◽  
...  
Keyword(s):  
Short Duration ◽  
Flow Analysis ◽  
The United States ◽  
Detailed Examination ◽  
Naval Academy ◽  
United States Naval Academy ◽  
Calm Water ◽  
Wedge Impact ◽  
Impact Experiments ◽  
Naval Surface Warfare

Numerical simulations of wedge impact experiments, undertaken by the Naval Surface Warfare Center, Carderock Division, NSWCCD, and more recently by the United States Naval Academy, USNA, Hydromechanics Laboratory, were performed using the computational fluid dynamics code Numerical Flow Analysis, NFA, to assess its capabilities in simulating the short duration hydrodynamic loading associated with free-surface impact. NSWCCD performed experiments using drop heights of 15.24 cm (6 in) and 25.4 cm (10 in), while the Naval Academy used drop heights of: 7.94, 12.7, 15.88, 25.4, 31.75, 38.1, and 50.8 cm (3.125, 5.0, 6.25, 10.0, 12.5, 15.0, and 20.0 in), measured from the keel of the wedge to the calm water surface. Simulations and comparisons were made at heights of 15.24 cm (6 in) and 25.4 cm (10 in) with the NSWCCD data, and 12.5 inches for the USNA data providing for a detailed examination of NFA’s ability to simulate and predict short duration hydrodynamic impacts.

Numerical Simulation of Dynamic Response of Planing Craft Sailing in Calm Water

2014 ◽  
Vol 590 ◽  
pp. 37-41
Author(s):  
Yu Min Su ◽  
Yun Hui Li ◽  
Hai Long Shen
Keyword(s):  
Numerical Simulation ◽  
Empirical Formula ◽  
High Speed ◽  
Evaluation Method ◽  
Simulation Method ◽  
Experimental Results ◽  
Planing Craft ◽  
Calm Water ◽  
Performance Evaluation Method ◽  
Good Agreement

In order to forecast the sailing response of planing craft at high speed rapidly and accurately, CFD code Fine/Marine solver was used to calculate the resistance and sailing attitude of a high-speed planing craft, then the numerical results were compared with experimental results and empirical formula results. The results showed that resistance error calculated by Fine/Marine was between 5% and 10%, trim and heave results were in good agreement with experimental results, and had greater accuracy compared with the empirical formula results. The feasibility of this numerical simulation method was validated and this method provided an effect performance evaluation method for new designing planing crafts.

Empirical Methods for Predicting Lift and Heel Moment for a Heeled Planing Hull

2014 ◽  
Vol 30 (04) ◽  
pp. 175-183
Author(s):  
Carolyn Q. Judge
Keyword(s):  
High Speed ◽  
Experimental Program ◽  
Naval Academy ◽  
Forward Speed ◽  
Empirical Methods ◽  
Empirical Relationships ◽  
Planing Craft ◽  
Underwater Photography ◽  
Calm Water ◽  
Transverse Stability

Even in calm water, high-speed vessels can display unstable behaviors such as chine walking, sudden large heel, and porpoising. Large heel angle can result in the loss of transverse stability at high forward speed. When a planing craft begins to plane, the hydrodynamic lift forces raise the hull out of the water, reducing the underwater geometry. An experimental program at the U.S. Naval Academy has been designed to investigate the transverse stability of planing hulls. An experimental mechanism to force a planing hull model in heave and roll motion was designed and built. The first model tested was a wooden prismatic planing hull model with a constant deadrise of 20, a beam of 1.48 ft (0.45 m), and a total length of 5 ft (1.52 m). The model was held at various heel and running draft positions while fixed in pitch, yaw, and sway. The tests were done at two model speeds, for one model displacement, five fixed heel angles, and five fixed running heave positions. The lift and sway forces, along with the heel moment, were measured and underwater photography was taken of the wetted surface. This article presents a set of equations based on empirical relationships for calculating the lift and heel moment for a prismatic planing hull at nonzero heel angles.

Yaw Galloping of a TLWP Platform Under High Speed Currents by Analytical Methods and its Comparison With Experimental Results

2017 ◽  
Author(s):  
Francisco Lamas ◽  
Miguel A. M. Ramirez ◽  
Antonio Carlos Fernandes
Keyword(s):  
High Speed ◽  
Production Systems ◽  
Experimental Tests ◽  
Experimental Results ◽  
Analytical Methodology ◽  
New Approach ◽  
Laboratory Facilities ◽  
Polynomial Curve ◽  
Computational Fluid Dynamics Cfd ◽  
Cfd Analyses

Flow Induced Motions are always an important subject during both design and operational phases of an offshore platform life. These motions could significantly affect the performance of the platform, including its mooring and oil production systems. These kind of analyses are performed using basically two different approaches: experimental tests with reduced models and, more recently, with Computational Fluid Dynamics (CFD) dynamic analysis. The main objective of this work is to present a new approach, based on an analytical methodology using static CFD analyses to estimate the response on yaw motions of a Tension Leg Wellhead Platform on one of the several types of motions that can be classified as flow-induced motions, known as galloping. The first step is to review the equations that govern the yaw motions of an ocean platform when subjected to currents from different angles of attack. The yaw moment coefficients will be obtained using CFD steady-state analysis, on which the yaw moments will be calculated for several angles of attack, placed around the central angle where the analysis is being carried out. Having the force coefficients plotted against the angle values, we can adjust a polynomial curve around each analysis point in order to evaluate the amplitude of the yaw motion using a limit cycle approach. Other properties of the system which are flow-dependent, such as damping and added mass, will also be estimated using CFD. The last part of this work consists in comparing the analytical results with experimental results obtained at the LOC/COPPE-UFRJ laboratory facilities.

The Effect of Strain Rate on the Material Characteristics of Nickel-Based Superalloy Inconel 718

2007 ◽  
Vol 340-341 ◽  
pp. 283-288 ◽  
Author(s):  
Jung Han Song ◽  
Hoon Huh
Keyword(s):  
Dynamic Response ◽  
High Strain Rate ◽  
Strain Rate ◽  
Turbine Blade ◽  
Inconel 718 ◽  
High Speed ◽  
High Strain ◽  
Split Hopkinson Pressure Bar ◽  
Experimental Results ◽  
Stress Wave Propagation

The dynamic response of the turbine blade materials is indispensable for analysis of erosions of turbine blades as a result of impulsive loading associated with gas flow. This paper is concerned with the dynamic material properties of the Inconel 718 alloy which is widely used in the high speed turbine blade. The dynamic response at the corresponding level of the strain rate should be acquired with an adequate experimental technique and apparatus due to the inertia effect and the stress wave propagation. In this paper, the dynamic response of the Inconel 718 at the intermediate strain rate ranged from 1/s to 400/s is obtained from the high speed tensile test and that at the high strain rate above 1000/s is obtained from the split Hopkinson pressure bar test. The effects of the strain rate on the dynamic flow stress, the strain rate sensitivity and the failure elongation are evaluated with the experimental results. Experimental results from both the quasi-static and the high strain rate up to 3000/s are interpolated in order to construct the constitutive relation that should be applied to simulate the dynamic behavior of the turbine blade made of the Inconel 718.

Experimental Study of Turbulent Macroinstabilities in an Agitated System with Axial High-Speed Impeller and with Radial Baffles

1996 ◽  
Vol 61 (6) ◽  
pp. 856-867 ◽  
Author(s):  
Oldřich Brůha ◽  
Ivan Fořt ◽  
Pavel Smolka ◽  
Milan Jahoda
Keyword(s):  
Experimental Study ◽  
Flow Field ◽  
High Speed ◽  
Experimental Results ◽  
Turbulent Regime ◽  
Frequency Of Occurrence ◽  
Visualization Method ◽  
Entire Flow

The frequency of turbulent macroinstability occurrence was measured in liquids agitated in a cylindrical baffled vessel. As it has been proved by preceding experimental results of the authors, the stochastic quantity with frequency of occurrence of 10-1 to 100 s-1 is concerned. By suitable choosing the viscosity of liquids and frequency of impeller revolutins, the region of Reynolds mixing numbers was covered from the pure laminar up to fully developed turbulent regime. In addition to the equipment making it possible to record automatically the macroinstability occurrence, also the visualization method and videorecording were employed. It enabled us to describe in more detail the form of entire flow field in the agitated system and its behaviour in connection with the macroinstability occurrence. It follows from the experiments made that under turbulent regime of flow of agitated liquids the frequency of turbulent macroinstability occurrence is the same as the frequency of the primary circulation of agitated liquid.

A Wavelength Interleaved DWDM ROF System with 60GHz Optical OFDM Signal

2011 ◽  
Vol 130-134 ◽  
pp. 2245-2248
Author(s):  
Yong Hong Ma ◽  
Chong Xiang Zhang ◽  
Pan Zhang
Keyword(s):  
High Speed ◽  
Radio Over Fiber ◽  
Experimental Results ◽  
Arrayed Waveguide Grating ◽  
Waveguide Grating ◽  
Access System ◽  
Ofdm Signal ◽  
The Future ◽  
Optical Ofdm ◽  
Arrayed Waveguide

we demonstrate a wavelength interleaved DWDM Radio-over-Fiber (ROF) system for providing 1-Gb/s OFDM signal in downlink and 1-Gb/s OOK data in uplink simultaneously. In this scheme, we use only one arrayed waveguide grating device at the remote node to realize both the de-multiplexing and multiplexing functions. The experimental results demonstrate that this scheme is feasible to the future broadband high-speed OFDM-ROF access system.

A Compound Vibratory Mode in High Speed Vibratory Tapping

2009 ◽  
Vol 69-70 ◽  
pp. 379-383 ◽  
Author(s):  
L. Wang ◽  
Gui Cheng Wang ◽  
J.H. Zhu ◽  
Hong Jie Pei ◽  
L.F. Lin
Keyword(s):  
Stainless Steel ◽  
High Speed ◽  
Experimental Results

Based on the investigation of two traditional vibratory modes, this paper puts forward a novel vibratory mode in high speed tapping. Vibratory tapping on stainless steel with all kinds of vibratory modes is carefully studied. Experimental results show that the new vibratory mode not only preserves the machining effect of the separable vibratory tapping, but also increases the life of tap. Therefore this study provides a new solution to increase the performance of high speed vibrat- ion tapping.

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